Thursday, July 18, 2013

PublishWSDL option in WSO2 ESB explained...

Lets say you are going to expose a web service by creating a proxy service. If you do not publish the WSDL of the web service you are exposing, then if you take the WSDL of the created proxy, it will only show the "mediate" operation. If a client wants to invoke the backend service via the proxy service, it needs to know the expected message format by the web service (parameters, their names etc.).

But, if you decide to publish the WSDL of the web service, then the WSDL of the proxy service will show all the operations which are available in the web service. This makes life easier to the client.
But publishing WSDL also exposes all the operations of the web service. What if you want to expose only a few operation to the clients? In that case, you can publish a WSDL with only the operations which you want to expose.

There is another advantage. Lets say the backend service operation expects three parameters to be sent (lets assume these are name,department and a permission level). We want the client to send only the name and department and we are planning to add the permission level to the request within the proxy service. In such a scenario, we can publish a modified WSDL which is expecting only the name and the department and inject the permission level within the proxy service.

Above are the use cases of PublishWSDL option available in WSO2 ESB. Although this is a simple thing, I couldn't find a place which explains this. So, hope this helps somebody.